Tubes and bottles made from thin-walled plastic or plastic laminated material are used for packaging of, for example, creams, ointments and various other viscous chemical/engineering preparations. Swedish Patent Application 8800548-3 describes an end-piece and a method for manufacturing tubes or bottles by butt-welding an end-piece in both ends of a tubular-shaped body portion of thin-walled plastic or laminated plastic material.
The advantage of manufacturing tubes or bottles in this way is that the need to transport bulky empty containers over long distances is avoided. Accordingly the method allows the private packager to produce his own tubes or bottles without comprehensive equipment.
The tube or bottle produced according to the above method can be filled with its product via its opening, after which a cap is affixed over the opening with the aid of, for example, screw threads.
In many cases, however, it is desirable to provide a container which has been sealed in a controlled environment so that the customer can confirm that the packaging is unopened. This results in enhanced quality, both for the packaging and its contents.
During production of such a sealed container it is advantageous that filling with the product occurs between the fitting of the first end-piece, preferably tubularly formed, and the second end-piece. It has, however, proven to be difficult to fit the second end-piece without the product in the body-portion open end fouling either the weld-seam or the sealing region. A contributory factor to this problem is, of course, the high production rate which can reach around two units per second.
It is possible to avoid this problem by increasing the so-called "head-space" volume between the product and the inner surface of the end-piece. This can, however, lead to negative consequences for the product if there is the risk that it can react with the air in the said head-space. Furthermore, the customer may discriminate against a container with a large head space volume since it does not appear to be completely full.